U.S. patent application number 09/912486 was filed with the patent office on 2002-03-21 for iris identifying apparatus.
Invention is credited to Hatano, Kouichi.
Application Number | 20020033896 09/912486 |
Document ID | / |
Family ID | 18766537 |
Filed Date | 2002-03-21 |
United States Patent
Application |
20020033896 |
Kind Code |
A1 |
Hatano, Kouichi |
March 21, 2002 |
Iris identifying apparatus
Abstract
Disclosed is an iris identifying apparatus comprising an
optical-axis aligning section which aligns the line of sight of a
target person to be picked up, who views a guide light through a
view window, with the optical axis of an image pickup device that
picks up the eye of the target person. The optical-axis aligning
section flickers the guide light and guides the line of sight of
the target person to the guide light, and turns on the guide light
when the image picked up by the image pickup device comes into
focus, thereby notifying the target person of the eye having
entered the image pickup distance.
Inventors: |
Hatano, Kouichi; (Tokyo,
JP) |
Correspondence
Address: |
Venable
P.O. Box 34385
Washington
DC
20043-9998
US
|
Family ID: |
18766537 |
Appl. No.: |
09/912486 |
Filed: |
July 26, 2001 |
Current U.S.
Class: |
348/333.03 ;
348/78; 382/118 |
Current CPC
Class: |
G06V 40/18 20220101 |
Class at
Publication: |
348/333.03 ;
348/78; 382/118 |
International
Class: |
G06K 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2000 |
JP |
281955/2000 |
Claims
What is claimed is:
1. An iris identifying apparatus for identifying a target person to
be picked up by extracting an image of an iris from a picked-up
image of an eye of said target person, comprising: a view window
into which said target person looks; an infrared illumination
having a peak wavelength in a range of infrared rays; an image
pickup device which has a sensitivity in said range of infrared
rays and picks up said image of said eye of said target person
through said view window; a guide light which has a peak wavelength
in a range of visible rays and guides a line of sight of said
target person through said view window; and optical-axis aligning
means for aligning said line of sight of said target person viewing
said guide light with a photographing optical axis of said image
pickup device.
2. The iris identifying apparatus according to claim 1, further
comprising image-pickup notification means for turning on said
guide light and notifying said target person of said eye having
entered an image pickup distance of said image pickup device.
3. The iris identifying apparatus according to claim 2, wherein
said image-pickup notification means turns off said guide light
when a focus value is 0 indicating a state where said image pickup
device is not picking up said image, turns on said guide light when
said focus value is equal to or greater than a predetermined
threshold value and flickers said guide light when said focus value
is smaller than said threshold value, and said focus value of 100
indicates that said image pickup distance is an optimal image
pickup distance.
4. The iris identifying apparatus according to claim 1, wherein an
optical axis of said infrared illumination crosses said
photographing optical axis connecting said eye to said image pickup
device, at an optimal image pickup distance.
5. The iris identifying apparatus according to claim 2, further
comprising a guide frame, provided between said optical-axis
aligning means and said guide light, for guiding said image of said
iris within a predetermined range with respect to an image pickup
field of said image pickup device.
6. The iris identifying apparatus according to claim 5, wherein
said guide frame has a shape which is similar to that of said guide
light and hides a part of said guide light when said image of said
iris comes off said predetermined range of said image pickup
field.
7. The iris identifying apparatus according to claim 1, wherein
said optical-axis aligning means is a hot mirror for passing
visible rays of said guide light to allow said visible rays to
enter said eye of said target person, and reflecting infrared rays
of said infrared illumination reflected at said eye of said target
person to allow said infrared rays to enter said image pickup
device.
8. The iris identifying apparatus according to claim 1, wherein
said optical-axis aligning means is a cold mirror for passing
infrared rays of said infrared illumination reflected at said eye
of said target person to allow said infrared rays to enter said
image pickup device located on a line extending from said view
window, and reflecting visible rays of said guide light to allow
said visible rays to enter said eye of said target person.
9. The iris identifying apparatus according to claim 1, further
comprising a mirror for reflecting visible rays of said guide light
whereby said visible rays reflected at said mirror enter said eye
of said target person via said optical-axis aligning means.
10. The iris identifying apparatus according to claim 1, wherein
said iris identifying apparatus is a handheld type iris identifying
apparatus into whose view window said target person looks while
holding said iris identifying apparatus by a hand.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an iris identifying
apparatus which identifies an individual by extracting the image of
an iris from the picked-up image of an eye of the individual.
[0003] 2. Description of the Related Art
[0004] As an iris identifying apparatus which identifies an
individual by extracting the image of an iris from the picked-up
image of an eye of the individual, there is a so-called handheld
type iris identifying apparatus which a target person to be picked
up (hereinafter simply called "target person") holds by a hand to
pick up the image of an eye of that person.
[0005] The handheld type iris identifying apparatus has an
infrared-sensitive image pickup unit located at the back of a cold
mirror which passes infrared rays and an infrared illumination laid
around the cold mirror.
[0006] There are a few guide lights over the cold mirror. The guide
lights are on initially, and are all turned off when the image to
be picked up comes into focus with the image pickup device inside
the image pickup unit.
[0007] The target person turns his eyes on the guide lights first,
and adjusts the distance between an eye and the iris identifying
apparatus in such a way that the guide lights are all turned off.
When the guide lights are all turned off, the target person keeps
the iris identifying apparatus at the position. Then, the target
person turns his eyes on the cold mirror and iris identifying
apparatus picks up the image of the eye while viewing the image of
the eye shown on the cold mirror.
[0008] A target person holds the handheld type iris identifying
apparatus and turns his eyes on the guide lights, then adjusts the
distance between an eye and the iris identifying apparatus in such
a way that the guide lights are all turned off, and directs the
line of sight to the cold mirror to pick up the image of the eye
after confirming that all the guide lights have been turned off. It
is difficult for a user, particularly, a novice to stably hold the
position of the image pickup unit during image pickup.
SUMMARY OF THE INVENTION
[0009] Accordingly, it is an object of the present invention to
provide an iris identifying apparatus which is easy to handle for,
particularly, a beginner.
[0010] To achieve the object, an iris identifying apparatus of the
invention comprises a view window into which a target person to be
picked up looks; an infrared illumination having a peak wavelength
in a range of infrared rays; an image pickup device which has a
sensitivity in the range of infrared rays and picks up the image of
the eye of the target person through the view window; a guide light
which has a peak wavelength in a range of visible rays and guides a
line of sight of the target person through the view window; and
optical-axis aligning means for aligning the line of sight of the
target person viewing the guide light with a photographing optical
axis of the image pickup device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a block diagram of an iris identifying apparatus
according to a first embodiment of the invention;
[0012] FIG. 2 is a front view of an image pickup unit;
[0013] FIG. 3 is an explanatory diagram showing a flickering
pattern of guide lights;
[0014] FIG. 4 is an explanatory diagram showing a light-ON pattern
of guide lights;
[0015] FIG. 5 is an explanatory diagram showing a light-OFF pattern
of guide lights;
[0016] FIG. 6 is a flowchart illustrating the operation of an iris
identifying apparatus shown in FIG. 1;
[0017] FIG. 7 is a block diagram of an image pickup unit according
to a second embodiment of the invention;
[0018] FIG. 8 shows a guide frame and guide lights which are seen
through a view window;
[0019] FIG. 9 is an explanatory diagram showing the relationship
among an image pickup field, the guide lights and the guide
frame;
[0020] FIG. 10 is a front view of an image pickup unit according to
a third embodiment of the invention;
[0021] FIG. 11 is a front view of the image pickup unit shown in
FIG. 10;
[0022] FIG. 12 is an explanatory diagram for explaining glass
reflection at the position of infrared illumination; and
[0023] FIG. 13 is a block diagram of an image pickup unit according
to a fourth embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Preferred embodiments of the present invention will be
described below with reference to the accompanying drawings. Like
or same reference symbols are given to those elements common to the
individual drawings.
[0025] First Embodiment
[0026] FIG. 1 is a block diagram of an iris identifying apparatus 1
according to the first embodiment of the invention, FIG. 2 is a
front view of an image pickup unit, FIG. 3 is an explanatory
diagram showing the flickering of guide lights, FIG. 4 is an
explanatory diagram showing the light-ON state of guide lights, and
FIG. 5 is an explanatory diagram showing the light-OFF state of
guide lights. The iris identifying apparatus 1, which is of a
handheld type, comprises an image pickup unit 2 and an identifying
unit 3. A target person who undergoes image sensing holds the image
pickup unit 2 by one hand and looks into it in one eye.
[0027] The image pickup unit 2 has a view window 5 formed in one
end face of a case 6, which houses an infrared illumination 7, a
hot mirror 8, a lens 9, an image pickup device 10 and guide lights
11 and has an operation switch 12 provided on the top surface. The
view window 5 has a size (about .phi.30 mm) large enough for one
eye 4 of the target person to look into.
[0028] The infrared illumination 7 is an LED (Light-Emitting Diode)
having a peak wavelength in the range of infrared rays. The
infrared illumination 7 is placed in such a manner that an optical
axis 14 (hereinafter referred to as "photographing optical axis
14") when the eye 4 of the target person is photographed by the
lens 9 and the image pickup device 10 having a sensitivity in the
range of infrared rays, such as CCD (Charge Coupled Device),
crosses the optical axis of the LED at the optimal image pickup
distance (that the brightest illumination is given when the eye of
the target person lies in the optimal image pickup distance).
[0029] The lens 9 is arranged in such a way as to provide the
optimal image pickup distance when the image pickup distance
between the eye 4 of the target person and the image pickup device
10 is, for example, about 150 mm.
[0030] The hot mirror 8, which serves as optical-axis aligning
means, reflects infrared rays and passes visible rays. The hot
mirror 8 is disposed in such a way that the line of sight, 15, of
the target person seeing the guide lights 11 coincides with the
photographing optical axis 14.
[0031] The guide lights 11 are LEDs having a peak wavelength in the
range of visible rays. The guide lights 11 are located at such a
position that the guide lights 11 are seen near the center of the
view window 5 as shown in FIG. 2 when the target person looks into
the apparatus through the view window 5. The guide lights 11 are
turned on when an image to be picked up (hereinafter referred to as
"target image") is in focus with the image pickup device 10.
[0032] The guide lights 11 flicker as shown in FIG. 3 when the
target image is not in focus, are turned on as shown in FIG. 4 when
the target image is in focus, and are turned off as shown in FIG. 5
when the image pickup is finished.
[0033] The identifying unit 3 has a central processing unit 16
(hereinafter referred to as "CPU 16"), memory 17 and input/output
port 18. The CPU 16 is connected to the infrared illumination 7 and
the guide lights 11 via the input/output port 18 by control cables
19 and 20, respectively. The CPU 16 is connected to the image
pickup device 10 via the input/output port 18 by a video cable
21.
[0034] The CPU 16 is connected to the switch 12 via the
input/output port 18 by a line 22.
[0035] The CPU 16 receives the image of the eye 4 of the target
person picked up by the image pickup device 10 and computes an
image-pickup focus value. The focus value is 0 when no image pickup
is taking place and is 100 when the target image is in focus, i.e.,
when the image pickup distance between the eye 4 of the target
person and the image pickup device 10 is the optimal image pickup
distance (150 mm).
[0036] The focus value is acquired by computing contrast values
between each pixel in a specific area of electric image data
converted by the image pickup device 10 and its adjoining pixels
around the former pixel based on the luminous signals of the
individual pixels extracted by an image processing section. That
is, the focus value is acquired based on the fact that the closer
to the optimal image pickup distance the image pickup distance
between the eye 4 of the target person and the image pickup device
10 approaches, the greater the contrast value becomes.
[0037] The CPU 16 turns on the guide lights 11 when the focus value
is equal to or greater than a predetermined threshold value (e.g.,
the focus value that is obtained when the image pickup distance
lies between 140 mm and 160 mm) and flickers the guide lights 11
when the focus value is smaller than the threshold value.
Therefore, the CPU 16 flickers on the guide lights 11 to guide the
line of sight of the target person to the guide lights 11 when the
target person looks into the view window 5, and turns on the guide
lights 11 when the picked up image of the eye 4 enters the image
pickup distance with respect to the image pickup device 10, thereby
notifying the target person of that event.
[0038] The operation of the iris identifying apparatus will now be
described. FIG. 6 is a flowchart illustrating the operation of the
iris identifying apparatus shown in FIG. 1. At the time of holding
the image pickup unit 2 by a hand and manipulating an iris image,
the target person presses the switch 12 and looks into the view
window 5 with a predetermined one eye 4.
[0039] In step S1, the CPU 16 checks if the switch 12 has been
depressed. When the switch 12 has been depressed, the CPU proceeds
to step S2. In step S2, the CPU 16 turns on the infrared
illumination 7 and flickers the guide lights 11 at the same
time.
[0040] The infrared rays are reflected at the eye 4 of the target
person, are reflected again at the hot mirror 8 and enter the image
pickup device 10. The visible rays from the guide lights 11 pass
the hot mirror 8 and travel toward the eye of the target
person.
[0041] In step S3, the CPU 16 receives the image of the eye 4 of
the target person picked up by the image pickup device 10 and
computes the image-pickup focus value.
[0042] In step S4, the CPU 16 checks if the focus value is equal to
or greater than the predetermined threshold value. The CPU 16 goes
to step S5 when the focus value is equal to or greater than the
predetermined threshold value, but returns to step S3
otherwise.
[0043] In step S5, the CPU 16 turns on the guide lights 11. The
light-ON action of the guide lights 11 notifies the target person
of the image of the eye having entered the image pickup distance so
that the target person fixes the position of the image pickup unit
2.
[0044] The CPU 16 extracts the image of an iris 4a from the
picked-up image of the eye 4 in step S6, and performs registration
or collation process according to the switch 12 in step S7. At this
time, the CPU 16 turns off the guide lights 11, notifying the
target person of the end of the image pickup process.
[0045] According to the first embodiment, the target person has
only to look into the view window and adjust the distance between
the eye and the image pickup device after seeing the flickering of
the guide lights 11 until the guide lights 11 are turned on. The
embodiment can therefore provide an iris identifying apparatus
which is easy to operate for any person who undergoes image
sensing, particularly, a beginner.
[0046] Second Embodiment
[0047] FIG. 7 is a block diagram of an image pickup unit according
to the second embodiment of the invention, and FIG. 8 shows a guide
frame and guide lights which are seen through the view window of
the image pickup unit.
[0048] The iris identifying apparatus of the second embodiment
differs significantly from the iris identifying apparatus of the
first embodiment in that an image pickup unit 30 has a guide frame
body 31, located between the guide lights 11 and the hot mirror 8,
which has a guide frame 31a and guides the center position of the
eye 4 of a target person to the center of the image pickup
field.
[0049] The diameter of the iris 4a is about 11 mm on average, so
that when the image pickup device whose picked-up image has a
resolution of about 640 pixels.times.480 pixels is used, the image
pickup field becomes 32 mm.times.24 mm.
[0050] Further, the iris identifying apparatus has a capability of
detecting the center position of the iris 4a (when the entire image
of the iris 4a is not in the image pickup field, the iris 4a is not
identified). Because of that capability, the center position of the
iris 4a should actually be guided within the range of 12 mm.times.9
mm with respect to the center of the image pickup field.
[0051] FIG. 9 is an explanatory diagram showing the relationship
among the image pickup field, the guide lights and the guide frame.
The size of the guide frame 31a is determined as follows. The
horizontal size X and vertical size Y of the guide frame 31a are
given by:
X=Z.times.M/L (1)
Y=B.times.M/L (2)
[0052] where with the eye 4 of the target person being positioned
at the position on the photographing optical axis 14 (passing the
center of the image pickup field) where the best iris image can be
picked up, L and M are respectively the distance between the eye 4
of the target person and the guide lights 11 and the distance
between the eye 4 and the guide frame 31a and, as shown in FIG. 8,
A and B are respectively the vertical size and horizontal size of
the guide lights 11.
[0053] In this situation, the target person sees the guide frame
31a and the guide lights 11 as shown in FIG. 8 through the view
window 5. Note that the view window 5 should be set apart from the
eye 4 of the target person by 30 to 40 mm.
[0054] If the distance (L-M) between the guide lights 11 and the
guide frame 31a is too large, the guide frame 31a would look
blurred when the eye is in focus with the guide lights 11. If this
distance is too short, it is equivalent to the situation where the
guide frame 31a is not provided and the guiding precision becomes
lower. In this respect, the guide frame 31a is placed at the
position that is apart from the guide lights 11 by a certain
distance and does not blur the guide frame 31a.
[0055] As the target person is previously notified of the entire
guide lights 11 completely fitted in the guide frame 31a as shown
in FIG. 8, the eye 4 of the target person can be guided into the
image pickup field of the image pickup device 10.
[0056] Because the operation of the iris identifying apparatus is
the same as the operation of the first embodiment, its description
will not be repeated.
[0057] According to the second embodiment, the provision of the
guide frame body between the hot mirror and the guide lights can
allows a target person himself or herself to guide one eye of the
target person to the position where the best iris image can be
picked up.
[0058] The iris identifying apparatus is designed in such a way
that when the distance between the view window and the eye of the
target person is 30 to 40 mm, the target person sees that the
entire guide lights completely lie in the guide frame and the best
iris image can be picked up. This limits the required operation on
the target person side to one directional operation of positioning
the eye closer to the image pickup unit, thus resulting in an
improved operability.
[0059] Third Embodiment
[0060] FIG. 10 is a front view of an image pickup unit according to
the third embodiment of the invention and FIG. 11 is a front view
of the image pickup unit shown in FIG. 10. The iris identifying
apparatus of the third embodiment differs from the iris identifying
apparatus of the second embodiment in the structure of an image
pickup unit 40.
[0061] The image pickup unit 40 has infrared illuminations 7 and 7
arranged on the respective sides of the view window 5 at a distance
S of about 40 mm between the two so that the infrared rays
reflected at one of glasses 41 a target person is wearing are
directed out of the image pickup field.
[0062] FIG. 12 is an explanatory diagram for explaining glass
reflection at the position of infrared illumination. In FIG. 12, a
distance A indicates the case where infrared illuminations 7a and
7a are arranged at the respective sides of the view window 5 at the
distance S of about 40 mm set between both illuminations (i.e.,
where the infrared illuminations are set closer to the eye of the
target person) and a distance B indicates the case where infrared
illuminations 7b and 7b are arranged in the image pickup unit 40 at
the distance S of about 40 mm set between both illuminations (i.e.,
where the infrared illuminations are set away from the eye of the
target person). Broken lines 42 indicate the image pickup
field.
[0063] When the infrared illuminations are arranged closer to the
eye of the target person, the infrared rays reflected at the glass
41 are unlikely to travel toward the image pickup field and hide
the iris image. When the infrared illuminations are arranged away
from the eye of the target person, however, the infrared rays
reflected at the glass 41 are likely to travel toward the image
pickup field and the reflected light and screen the iris image.
[0064] Because the operation of the iris identifying apparatus is
the same as the operation of the second embodiment, its description
will be omitted.
[0065] According to the third embodiment, as the infrared
illuminations are arranged at the respective sides of the view
window and close to an eye of a target person at a distance of
about 40 mm set between both illuminations, the infrared rays
reflected at one of the glasses on the target person are unlikely
to travel toward the image pickup field and hide the iris image, so
that a good iris image can be acquired.
[0066] Fourth Embodiment
[0067] FIG. 13 is a block diagram of an image pickup unit according
to the fourth embodiment of the invention. The iris identifying
apparatus of the fourth embodiment differs significantly from the
iris identifying apparatus of the third embodiment in that the
guide lights 11 are provided above the view window 5, mirrors 51a
and 51b are arranged between the hot mirror 8 and the guide lights
11 and the distance between the hot mirror 8 and the guide lights
11 is increased considerably so that the visible rays from the
guide lights 11 are reflected at the mirrors 51a and 51b and reach
the eye of a target person through the hot mirror 8.
[0068] According to the fourth embodiment, the significant increase
in the distance between the view window and the guide lights makes
the apparent distance longer so that even a farsighted person can
clearly see the guide lights.
[0069] Further, as the apparent distance is made longer by the
combination of reflections of the mirrors, the image pickup unit
can be made compact.
[0070] Although a hot mirror is used in the first to fourth
embodiments, a cold mirror may be used on the condition that the
location of the image pickup unit and the location of the guide
lights are switched.
[0071] Although a handheld type iris identifying apparatus has been
illustrated as one example in the foregoing description of the
first to fourth embodiments, the invention can be adapted to a
fixed type iris identifying apparatus as well.
* * * * *